In recent years, touch panels are used for operation sections of various electronic devices including mobile telephones, portable information terminals, and car navigation systems. The touch panel is formed by an input device capable of detecting a position touched by a finger or the like being bonded onto a display screen for use in a display device such as a liquid crystal panel. Input devices of the touch panels are classified into various types of input devices such as resistive film type input devices and electrostatic capacitance type input devices, depending on a structure and a detection mode. Among them, the electrostatic capacitance type input devices each have translucent conductive films (translucent electrodes) formed on one substrate, and identify a touched position by detecting change of an amount of low power electric current flowing through electrostatic capacitance (which is generated by touching of a finger or the like), and the electrostatic capacitance type input devices are advantageous in that transmittancy can be enhanced, as compared to the resistive film type input devices.
FIG. 6 is a plan view schematically illustrating a structure of a conventional electrostatic capacitance type input device described in Patent Literature 1, and FIG. 7 is an enlarged cross-sectional view taken along a line VII-VII shown in FIG. 6.
An electrostatic capacitance type input device 91 includes, on a substrate 92, a plurality of X-axis traces 93 which extend in the X-axis direction (upward/downward direction in the drawings), and a plurality of Y-axis traces 94 which extend in the Y-axis direction (the leftward/rightward direction in the drawings), and which intersect the X-axis traces 93. The electrostatic capacitance type input device 91 detects positions touched by a finger or the like in the X-axis direction and the Y-axis direction.
The X-axis traces 93 are each formed by a plurality of transparent electrodes 95 aligned in the X-axis direction being connected to each other. On the other hand, the Y-axis traces 94 are each formed by a plurality of transparent electrodes 96 positioned intermittently in the Y-axis direction being electrically connected to each other through jumpers 99 formed of an electrically conductive material. The jumpers 99 are formed on an insulating film 97 which is layered over the X-axis traces 93 and the Y-axis traces 94, so as to extend above and across portions (portions each connecting between a pair of transparent electrodes 95 adjacent to each other) of the X-axis traces. The jumpers 99 are connected to the transparent electrodes 96 via through holes 98 located on the transparent electrodes 96.
Thus, in the structure described in Patent Literature 1, an insulating film is formed over the entire surface of the substrate 92 so as to insulate the X-axis traces 93 from the jumpers 99 extending above and across the X-axis traces, and the through holes 98 are formed in only portions in which the jumpers 99 are connected to the transparent electrodes 96.
Further, according to Patent Literature 2, a structure is described in which insulating films are formed in only positions across which jumpers extend, instead of an insulating film being formed over the entire surface of a substrate.